1. Field of the Invention
The present invention relates to thin-film magnetic recording heads used as floating magnetic heads and the like. In particular, the present invention relates to a thin-film magnetic head which generates a leakage magnetic flux at a proper position and meets trends toward higher density and higher recording frequencies and to a method for making the same.
2. Description of the Related Art
FIG. 17 is a partial front view of a structure of a conventional thin-film magnetic head (an inductive head). The thin-film magnetic head has a lower core layer 1 formed of a magnetic material, such as permalloy, and an insulating layer 9 formed on the lower core layer 1.
The insulating layer 9 has a groove 9a which extends from a face opposing a recording medium (hereinafter, referred to as an air bearing surface or ABS) in the height direction (the Y direction in the drawing) and has an inner width equal to the track width Tw.
A lower magnetic pole layer 3 which is magnetically coupled with the lower core layer 1, a gap layer 4, and an upper magnetic pole layer 5 which is magnetically coupled with the substrate holder 6 are formed by plating from the bottom of the groove 9a. 
A coil layer having a spiral pattern (not shown in the drawing) is provided on the insulating layer 9 in the height direction (the Y direction in the drawing).
The coil layer is covered by a coil insulating layer (not shown in the drawing) such as a resist layer, and the coil insulating layer is covered by an upper core layer 6. The edge of the upper core layer 6 is magnetically coupled with the upper magnetic pole layer 5.
In the production of the inductive head shown in FIG. 17, the insulating layer 9 is formed on the lower core layer 1, and then the groove 9a extending from the ABS and having the track width Tw and a predetermined length in the height direction is formed in the insulating layer 9.
Next, the lower magnetic pole layer 3, the gap layer 4, and the upper magnetic pole layer 5 are formed in the groove 9a by plating. The coil layer is formed on the insulating layer 9 behind the groove 9a in the Y direction by patterning. The coil layer is covered with the coil insulating layer, and then the upper core layer 6 is formed over the upper magnetic pole layer 5 and the coil insulating layer by a frame plating process to complete the inductive head shown in FIG. 17.
In this inductive head, a recording current flowing in the coil layer induces a recording magnetic field in the lower core layer 1 and the upper core layer 6. A leakage magnetic field generated between the lower magnetic pole layer 3 magnetically coupled with the lower core layer 1 and the upper magnetic pole layer 5 magnetically coupled with the upper core layer 6 is recorded as magnetic signals on a recording medium such as a hard disk.
In this inductive head, the lower magnetic pole layer 3, the gap layer 4, and the upper magnetic pole layer 5 having the track width Tw are locally formed in the vicinity of the ABS (the face opposing the recording medium). Such an inductive head is suitable for narrower track widths.
However, almost no studies on forming a gap layer not having magnetism of a thin-film magnetic head by plating have been performed in consideration of various conditions including the composition of a metallic material to be used.